a) Field of the Invention
The invention is directed to an electric probe for microsurgery which is provided in particular in ophthalmology for intraocular treatments of the eye, comprising two electrodes which are arranged coaxial to one another, a light guide which is formed as an insulator preferably being arranged therebetween, wherein the inner electrode and the outer electrode have means for connecting to an operating and controlling device.
b) Description of the Related Art
The use of probes of the kind mentioned above in eye surgery for electrosurgical cutting, ablation or coagulation of tissue is known. When using an electrosurgical probe in surgical operations on the eye, it is problematic to ensure adequate illumination of the interior of the eye or of the fundus of the eye so that illumination is often used in addition to the surgical implement and is guided in through a second puncture. This makes the performance of the operation itself more complicated and also increases stress on and risk to the patent. Another great problem in intraocular treatments of the eye is that currently used cutting implements produce relatively large incisions and the surgeon must move these cutting implements relative to the tissue causing additional tensile and compressive stresses which can lead to unwanted damage to the tissue. Another problem is intraocular illumination. For this reason, probes such as those described in DE 101 18 464 A1 are used to improve the illumination conditions at the operating location of the probe which comprises two electrodes that are connected to a power supply unit and are coaxial to one another, a light guide connected to a light-generating unit being provided between these electrodes.
Further, DE 195 42 955 C2 describes an endoscope with a flexibly constructed cannula whose outer diameter is less than one millimeter and which has light-conducting fibers in the hollow space of the cannula for illuminating the space to be examined and image fibers for transmitting an image of the illuminated space.
U.S. Pat. No. 6,135,998 discloses a method for handling a probe for microsurgery having an inner electrode for use in liquid media. The contour surrounding the inner electrode in the end area at which microplasma threads are formed after an electrical discharge process is constructed of electrically conductive material in a circular or elliptic shape.
Another problem in intraocular treatment of the eye consists in that it is often necessary to detach membranes from one another intraocularly. For this purpose, the membrane to be removed must usually be lifted with forceps and the cutting instrument, e.g., a plasma knife, is introduced between the membrane and the retina in order to detach the synechia or adhesions by plasma cutting. The probe tip itself presents a considerable source of interference in that, on one hand, the electrode tip, when introduced frontally, makes it difficult to carry out lateral ablation between the membrane and retina and, on the other hand, unwanted liquid currents occur that are directed away from the tip. The strength of the currents and the effective depth of the probe shape depend on the electrical energy supplied, so that a destructive action occurs in axial direction and can result in damage to blood vessels or blood-conducting surface capillaries.